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Finding the Fourth Proportional to 821.90, 1,230.45 and 725.90

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Solution

The fourth proportional to 821.90, 1,230.45 and 725.90 is: 1,086.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.90 : 1,230.45 = 725.90 : x
  2. Step 2: Convert to fraction form
    821.90/1,230.45 = 725.90/x
  3. Step 3: Cross multiply
    821.90x = 1,230.45 × 725.90
  4. Step 4: Simplify right side
    821.90x = 893,183.66
  5. Step 5: Solve for x
    x = 893,183.66/821.90
  6. Step 6: Final answer
    x = 1,086.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.